Derrick



NOV- 19, 1953 .1.R. MILLER ETAL DERRICK 5 Sheets-Sheet l Filed May 18, 1962 INV El? JosePH E. M\\ L CAEL. o. wmsoN ATTOR N EYS Nov. 19, 1963 Filed May 18, 1962 J. R. MILLER ETAL DERRICK 3 Sheets-Sheet 2 @i El 46 56 2Q Immnuml 32 J 'u JQ@ INVENTORS JOSEPH \2.M|L\.E\2

CARL O vvsLsoN ATTORNEYS NOV- 19, 1953 J. R. MILLER ETAL 3,111,225

INVENTORS Jose PH E. Ml I LE E, gaetan. o -wlLsoN ATTolz N EY United States Patent 3,lll,225 DERRCK Eoseph R. Miller, 2.538 N. Zth St., and Cari Wilson, 3l7 E. Reeser Road, both of Phoenix, Ariz. Filed May 18, 1962, Ser. No. 195,779 il Claims. (Ci. ZiZ-S) This invention relates to a derrick, and in particular to a derrick for use on a service truck, such as those used by construction, repair and maintenance crews emplojf'ed by utility companies in work on power or telephone lines. Such trucks usually carry a considerable complement of tools, equipment, and materials, land therefore comprise a body of substantial capacity and height. This creates a problem in respect to stowage of the crane or derrick, when not in use, especially since the work requires booms of considerable length, in contrast to the booms used, for instance, on open-body ltow trucks.

This situation has led to proposals Ifor boom structures facilitating stowage, including booms arranged Ifor folding action intermediately of their length, and it is -a general object of the present invention to provide an improved derrick of this type. The aforesaid proposa-ls have entailed serious shortcomings, due for the most part to the requirement for mechanical locking features, either requiring hand manipulation, or some form of operator control, and it is therefore 4a more particular object to provide a foldable boom which avoids the need for interlocking fastening means for the unfolded boom. The prior proposals have also involved more or less complex structure, and high cost, and it is a further object to provide improvements in respect to these factors.

In still greater particular, it is `an object to provide a foldable derrick boom with an articulated pair of lower legs, a pair of upper legs joined in an apex and articulated to the lower legs, the upper legs adapted to pick up :and carry the lower legs after `alignment therewith, and spring means providing a bias constantly urging the lower legs to the position of pick-up by the upper legs.

These and other ends, which will be readily apparent, are attained by the present invention, a preferred form of which is described in the following speciiication, as illustrated in the drawings, in which:

FGURE l is a top plan view of the body portion of a truck, with the derrick mounted thereon, the latter being shown in folded, stowed position,

FGURE 2 is a side elevational View of the parts shown in FIGURE l, with two adjusted positions of the derrick lboom indicated in dash lines,

FIGURE 3 is a rear elevational view ofthe parts shown in FIGURE 2, with the adjusted, vertical position of the boom indicated in dash lines,

4lGURE 4 is a fragmental, perspective view of a detail of the pivotal mounting of one of the lower legs of the boom, enlarged in scale,

FIGURE 5 is `a rear elevational view of the elements shown in FIGURE 4,

FIGURE 6 is a sectional view taken on the line 6 6 of FlGURE 5,

FIGURE 7 is a sectional View taken on the line 7-7 of FIGURE 5, and

FIGURES 8 and 9 are fragmentary views, similar to FIGURE 3, showing modiiied spring-biasing means.

Referring to the drawings by characters of reference, there is shown 1a trucl: body, indicated generally by the numeral 1', with open rear end, and vertical side walls l2. Supported on the door of the truck body, within side walls 12, is a mounting framework for the derrick boom, comprising channel members, including uprights lli, diagonal braces 16, and top members i8.

As shown by the dash lines in FIGURE 3, the boom,

ICC

when unfolded to working adjustment, is in the form of an inverted V, and comprises a pair of lower legs 20 pivotally connected respectively, to a pair of upper legs 22. Since the legs of each pair are similar on 4the two sides of the lcentral plane of symmetry of the boom, except for being arranged in mirror-image relationship, only one set need be described. Preferably the leg components are formed from tubular stock, and these are flattened at each end to receive the several swing pivots, and the shaft of a sheave 24 at the apex of the boom.

As seen in FIGURES 4 and 5, the flat, lower end Z6 of leg 20, which is bent to slant the lower legs into conformity with the V form of the lupper legs, is bored -to receive a bushing sleeve 2S, which is rotatably mounted on `a xed pin =or shaft Sil, `carried -by a pair of brackets 32, suitably secured, as by welding to the truck body, on the rear faces of side walls 12. Each of the lower legs 2h is biased to a vertical, upright attitude by means of a torsion coil spring 34, surrounding the pin 3%, and having one end portion 36 engaged in a tubular element 33, which is welded to the rear edge of flat section 26 of the leg. The other end lil of the spring is yalso bent, and received in a tube 42, carried on the tangentially extending skirt 44 of a .sleeve 46, rotatably mounted on the pin 34D, the skirt having reinforcing side webs 48. Rotation of the sleeve 46, in one dineotion, is resisted by the head of a Ibolt Sil, the latter being received in an opening 52. in the skirt 44, and an opening 54 in a shelf plate 56 carried by brackets 32., and secured beneath the plate by a nut d. The loading of the spring 34 is such as to `at least carry the leg Ztl' to the upright position shown in lfull lines in the several figures of the drawing, :and preferably will be subject to some degree of loading at this position. The spring loading is adjustable by means of the bolt 5d, and since adjustment will involve different positions of inclination of the bolt, the lower opening 54 is made in frusto-conical form, and the upper opening 52 is made somewhat larger than the bolt shank diameter.

The upper legs 22 are articulated to the lower legs 20 by pivot pins 6l), the co-acting, flattened ends of the tubes being arranged so that the pins -are arranged on a common vhorizontal axis. This arrangement comports with motion of .the vertex end of the boom in a vertical plane, `and avoids binding of the pivot and bending of the legs. Alternatively, universal joints may be employed, and it is also possible to position the lower legs vertically, in which case, it is only necessary to bend the lower ends of the upper legs to achieve the horizontal pivoting.

At their lower ends, the upper legs 22 each carry a semi-tubular sleeve 62, which extends beyond the pivotal connection with the lower legs. As shown these sleeves are sections of channel stock, but they may also be lformed from round, tubular stock. In the activation of the boom the V Isection formed by the upper legs first rotates about the axis of pivot pins 6i?, and at a position just beyond the vertical, this section becomes co-planar with the lower legs, and the extended portion of sleeves, or jackets 62, engage the rear sides of lower legs 2li, after which the lower legs are carried with the upper legs in their swing, against the opposition of spring 34. Any loading on top of the boom after this Contact is made only serves -to further guarantee the unitary character of the boom. Upon retrograde movement of the boom, whether lcarrying a load or not, the spring constantly urges the lower legs to their normal position in or near a vertical plane.

The boom is initially lifted, and its inclination controlled at all stages by a hydraulic system, comprising a pair of :tubular members 64 telescopically mounted, respectively on cylindrical members o6, for sliding movement thereon. The inner members e6 are pivoted, for swinging movement, yon pins 68, secured in forked brackets 79, mounted on top rails i8 of .the framework, at the rear ends thereof. As in the case of pins 6d, the pins 7i? are preferably aligned on a common, horizontal axis, and the lower ends of inner members 65 are bent into Iperpendieularity with this axis, although a universal linkage could also Ibe employed. At their upper ends the outer tubes 64 `are pivoted to the respective, upper boom members 22, by pivot pins 72, carried by brackets 74 on members 22.

Swingin'3 of .the boom, about the axis of pins 6d, or of pins Sii, as the case may be, is effected by sliding movement of sleeves 64, along inner members 66. This is preferably accomplished by hydraulic pressure, and the particular arrangement, which forms no part of the present invention, may partake of any lof several known and accepted forms. For the embodiment shown, it sufiices to say that the fluid pressure is introduced selectively, through either of -two lines 76, '78 leading into the inner member 65, the latter constituting a 'hydraulic cylinder, accommodating a piston which is attached to, and carries, the outer sleeve 64. IThe hydraulic pressure may be utilized to lift the `derrick from stowed position, and carry it to working position, where loads may be lifted by means of a cable iii), wound on a winch S2, on the truck lbed, trained over the sheave 24, and carrying a lifting hook S4. During load lifting, the boom is held in adjusted position by a neutral setting of the hydraulic pressure on the piston, and if it is desired to move the boom, to place a load within the truck, for instance, the pressure on the piston is Iapplied in the appropriate direction. In lthis regard, it should Ibe noted that the provision of two hydraulic arms leaves the space between .the boommembers free for passage `of the load therebetween. it is also possible to combine the efforts of the winch and the hydraulic system in 'straight lifting.

The particular, coil spring means 'applied to the flower 'members of the boom are not limiting, since other forms may be employed without departing from the concept of n constantly acting, automatic bias acting against rearward swing of the lower part 4of the boom. For instance, torsion bars may be employed in lieu of the coil springs, since the maximum swing yis only :about 90. Thus, in FiGURE 8, the legs Z9 rof the boom are swingably mounted on respective pins S6, ycarried by blocks or brackets 88, ixed to w-alls 12. A tube 90 of spring material, is carried at its center in the head 92 of a standard 94, the base 95 of which is secured to `the truck bed. The tube i3 held against rotation at its center by any convenient means, SUCh as one or more lines of welding 9S, and 'the ends of the tube are lalso secured to legs 2G by suitable means, such as lines of welding 16d, so as to twist when the legs are swung, as indicated schematically by the curved arrows in the figure. Of course, the position of minimum torsional stress -in the tube is that corresponding to the vertical position of legs 2d, with the stress increasing as the legs swing rearwardly and downwardly.

.in order to minimize strain in the torsion tube, a single section thereof may be employed, enabling greater length in the tube. This is illustrated in FIGURE 9, wherein the standard 94 is shown as located in `spaced relation to the longitudinal center-line of the vehicle, and near one of the legs 2t), thus permitting use of the longer, sin- ;gle section of tube 192, the lines of welding 98 being indicated at head 92 and the leftward leg 26. rIlhe pin .104 on the rightward leg 2i) has a keeper head 106 to retain the leg in place.

As in the case of the single sec-tion of torsion bar, it yis also possible to use any other type of spring on `one -only of the legs, for instance, by omitting one of the coil springs 34.

Generally speaking, various other modications are possible, and will become apparent in the light of this disclosure, and ,the invention should not, therefore, b@

deemed as limited, except insofar as `shall appear from the spirit and scope of the appended claims.

What is claimed is:

l. A derrick comprising a mounting framework, a pair of brackets carried by said framework, in spaced relation, a shaft carried by each of said brackets, and arranged on a common axis, a lower arm carried by each of said shafts, and arranged for swinging movement about the axis thereof, said lower Varms also arranged in converging relation outwardly of said axis, said framework limiting swing of said lower arms to a vertical position, an upper arm articulated to each of said lower arms at their distal ends, arranged for swinging movement on a common axis, and converging a-t the same angle as the angle of convergence of said lower arms and joined to form fan apex, a sleeve of channel-form section carried by each upper arm near its axis of swing and extending therebeyond, in position to engage the said lower yarm-s when the upper arms are 1n a position substantially co-planar with the lower arms, means for swinging the upper arms comprising a hydraulic system, with a piston and cylinder having one component pivoted to one of said upper arms and the other component pivoted .to said framework, in. spaced relation, and a coiled, torsion spring on each of said shafts, with one end anchored to the associ-ated lower arm, and the other end fixed against rotation about the axis of said shaft.

2. In a device as in claim l, means for adjusting the position of the ixed end of said spring, angularly of said shaft.

3. In a device as in claim l, means for adjusting the torsional load on said spring.

4. A derrick comprising a mounting framework, a pair of brackets carried yby said framework, in spaced relation, a shaft carried by each of said brackets, and arranged on a common axis, a lower arm carried by each of said shafts, and arranged for swinging movement about the axis thereof, said lower `arms also arranged in converging relation outwardly of said axis, said frame-work limiting swing of said lower arms to a vertical position, an upper arm articulated to each of said lower arms at the-ir distal ends arranged for swinging movement .on :a common axis, and converging at the same angle as the angle of convergence of said lower arms and joined to form au apex, a sleeve of channel-form sect-ion carried by each upper arm near its Iaxis of swing and extending therebeyo-nd, in position to engage the said lower arm-s when Ithe upper arms are in a position substantially co-planar with the lower arms, means for `swinging the upper arms comprising a hydraulic system, with a piston and cylinder having one component pivoted t-o one of said upper arms and the other cornponent pivoted to said framework, in spaced relation and spring means associated with said lower legs, and urging Athem in a direction of swing opposite to :the direction of swing of said upper arms required to bring said sleeves in contact with said lower arms.

5. A device as in claim 4, said spring means comprising a torsion bar.

6. A derrick comprising a mounting framework, a pair of spaced, coaxial shafts carried by said framework, a lower arm carried by each of said shafts, and arranged for swinging movement about the axis thereof, to a limiting, vertical position, a pair of upper arms, meeting in a vertex and articulated to said lower arms, a member carried by each of said upper arms, extending beyond the axis of articulation thereof, and adapted to contact the lower arms when the upper and lower arms are substantially co-planar, power means to swing the upper arms, and Ia coil spring ou at least one of said shafts, with one end engaging the associated lower arm to urge it .to vertical position, and the other end fixed against rotation about the shaft.

7. "In a device as in claim 6, means for adjusting the position of fixed end of said spring, angulanly of said shaft.

S. In a device as in claim 6, means for adjusting the torsional load on said spring.

9. A derrick comprising a mounting framework, a pair of spaced, coaxial shafts carried by said framework, a lower arm carried by each of said shafts, and arranged for swinging movement about the axis thereof, to a limiting, vertical position, a pair of upper arms, meeting in a vertex and articulated to said lower arms, a member carried by each of said upper arms, extending beyond the axis of a-rticulation thereof, and adapted to contact the lower arms when the upper and lower arms are substantially coplanar, power means to swing the upper arms, and spring means associated with said lower legs, and urging them to said limiting, vertical position.

10. A device as in claim 9, said spring means comprising a torsion bar.

11. A device as in claim 9, said power means acting between said framework and at least one of said upper arms, and positioned apart from the path of sweep of said upper arms.

References Cited in the le of this patent UNITED STATES PATENTS 2,886,187 Troche May 12, 1959 2,838,149 Troche May 26, 1959 3,043,398 Bakula July 10, 1962 

1. A DERRICK COMPRISING A MOUNTING FRAMEWORK, A PAIR OF BRACKETS CARRIED BY SAID FRAMEWORK, IN SPACED RELATION, A SHAFT CARRIED BY EACH OF SAID BRACKETS, AND ARRANGED ON A COMMON AXIS, A LOWER ARM CARRIED BY EACH OF SAID SHAFTS, AND ARRANGED FOR SWINGING MOVEMENT ABOUT THE AXIS THEREOF, SAID LOWER ARMS ALSO ARRANGED IN CONVERGING RELATION OUTWARDLY OF SAID AXIS, SAID FRAMEWORK LIMITING SWING OF SAID LOWER ARMS TO A VERTICAL POSITION, AN UPPER ARM ARTICULATED TO EACH OF SAID LOWER ARMS AT THEIR DISTAL ENDS, ARRANGED FOR SWINGING MOVEMENT ON A COMMON AXIS, AND CONVERGING AT THE SAME ANGLE AS THE ANGLE OF CONVERGENCE OF SAID LOWER ARMS AND JOINED TO FORM AN APEX, A SLEEVE OF CHANNEL-FORM SECTION CARRIED BY EACH UPPER ARM NEAR ITS AXIS OF SWING AND EXTENDING THEREBEYOND, IN POSITION TO ENGAGE THE SAID LOWER ARMS WHEN THE UPPER ARMS ARE IN A POSITION SUBSTANTIALLY CO-PLANAR WITH THE LOWER ARMS, MEANS FOR SWINGING THE UPPER ARMS COMPRISING A HYDRAULIC SYSTEM, WITH A PISTON AND CYLINDER HAVING ONE COMPONENT PIVOTED TO ONE OF SAID UPPER ARMS AND THE OTHER COMPONENT PIVOTED TO SAID FRAMEWORK, IN SPACED RELATION, AND A COILED, TORSION SPRING ON EACH OF SAID SHAFTS, WITH ONE END ANCHORED TO THE ASSOCIATED LOWER ARM, AND THE OTHER END FIXED AGAINST ROTATION ABOUT THE AXIS OF SAID SHAFT. 